Standardize usage of virtual/override/final specifiers.

remoting/host/heartbeat_sender_unittest.cc

Index: remoting/host/heartbeat_sender_unittest.cc
diff --git a/remoting/host/heartbeat_sender_unittest.cc b/remoting/host/heartbeat_sender_unittest.cc
index fb8aceeb1715b0ce4206f5b2c937c39a7ec217b0..2760cd4b354538657e1eb6508ac9a9557ac9a089 100644
--- a/remoting/host/heartbeat_sender_unittest.cc
+++ b/remoting/host/heartbeat_sender_unittest.cc
@@ -65,7 +65,7 @@ ACTION_P(RemoveListener, list) {
 class HeartbeatSenderTest
     : public testing::Test {
  protected:
-  virtual void SetUp() override {
+  void SetUp() override {
     key_pair_ = RsaKeyPair::FromString(kTestRsaKeyPair);
     ASSERT_TRUE(key_pair_.get());
 
@@ -82,7 +82,7 @@ class HeartbeatSenderTest
         &mock_listener_, kHostId, &signal_strategy_, key_pair_, kTestBotJid));
   }
 
-  virtual void TearDown() override {
+  void TearDown() override {
     heartbeat_sender_.reset();
     EXPECT_TRUE(signal_strategy_listeners_.empty());
   }